Balanced centrifugal pump.



G. GOMSTOCK.

BALANGED OENTRIPUGAL PUMP.

APPLICATION FILED AUG. 30, 1911. RENEWED AUG-.14, 1913. 1,0 5,020, Patented Jan. 20, 1914.

3 SHEETSSHBBT 1. r

Witness es: 112120121012 7M 6 (Tiles fer ('omsioclc Bysflflorney U. C(JMSTOOK.

BALANCED GENTRIFUGAL PUMP.

APPLICATION FILED AUG. 30, 1911. RENEWED AUG. H, 1913v 3 SHBETS-SIIEET 2y I q Elba-495$ 85'. Inventor: 5W 5. f3 m h 621981 6" 0112510011? jam-Jamm O. GOMSTOGK.

, BALANCED CENTRIFUGAL PUMP.

, APPLICATION FILED Anehso, 1911. RENEWED AUG. 14, 1913.

1 ;085,020, Patented Jan. 20, 1914.

3 SHEETS-SHEET 3.

Wihpesses: Inventor:

I Chester [OJIlStOCIf Byhis Attorney UNITED arnum OFFICE.

' CHESTER COMSTOCK, OF YORK, N. Y.. ASSIGNOB OE ONE-HALF TO CHARLES LEFFLER, OF BROOKLYN, NEW YORK.

BALANCED CENTRIFUGAL PUMP.

- Specification of I.etters Patent.

" Application filed August 30, 191i, Serial no. 646,814. Renewed August: 14, 1913. Serial No. 754,791.

To all whom it may concern:

Be it known that I, CHESTER COMS'IOCK, acitizen of the'United States, residing in New York city, in the county of Kings and State of New York, have invented certain new and useful Improvements in Balanced Centrifugal Pumps, of which the following is a specification. a

My, present invention relates to an improven ent in centrifugal pumps, but more especially to a rearrangement of the impeller units, such asare described andclaimedin 'my concurrently pending application, Serial him-621,969, filed April 19, 1911, wherein a series of peculiarly designed and operating impelhng hnlt members are shown arranged in series, all of said impeller units propelling fluid in one direction fromthe' inlet to the exhaustports.. In my presentimprovement I have rearrangedthese same impeller units m n-new manner m'orclertov increase. the

,etliciency of the pump, as 11:;Wl10l6, by decreasing the'intern'al friction caused bv'lthe' end thrust, thereby reducing the wear (if the parts. I havediscovered that if the impeller members of acentrifugal Jump are .caused to rotate in certain well de ned positions in relation to the stationary or coacting parts, greatly increased efficiency may be obtained. I have also found that to rely entirely for this steadiness of position upon ansautomatic balancing of the pressure on the sides of the impellers, does not, owing to the varying conditions of suction and discharge. always produce the desired results, and the effect is a reduced ctiiclency and an undesirable wez lring'of the parts which sustain the end thrust. caused by this unbal: anced condition. while on the other hand it is not. desirable to carry the entire load (if the pump by thrust. bearings, for various well known reasons.

' The object of this invention is to maintain the impellers in their most advantageous position for ctlicicut 'scr\-'ice,"\\ith tluvsmallcst amount of 't'rict ion and -\\'ear. 0n the parts which must come in contact. in securing this steadiness of position.

The above re ults 'are accompli hei'l in part. automatically, by arranging the impclhl's in opposition to-one another. it this is meant that one of 'thc impellers with its co-arting guide blades is reversed as relate to the dircrtion of its discharge wlicrc by the tort-c ot' the dischargeoithis'rcii'crscd pump unit is caused to counteract the force of the discharge of the other pump units as relates to the end thrust of the shaft, and, by providing a balancingchamber for each impeller a partial balancing effect is secured for that impeller by means of the leakage,-

which is incidental to the construction and operation of the pump. A further balancing provision is made by means of a connccting passage from the balancing chamber of the reversedimpeller to one .or more of the balancing chambers in the preceding series. This automatic operation will be more full) described hereinafter. I

A further improvement in this device is in the use of a'manually adjustable valve controlling mcans, whereby I-am .enabled to adjustably direct and maintain the fluid pressures so that a pressure 'from high pres- -surechamber, such as the discharge chamber, is admitted to a low pressure balancing clnunber through a valve-controlled ort to a uy desired amount, to'the limit of said high pressure, thereby obtaining a regulating means for balancing the impeller units, said regulating means being variable at will. 4

A further advantage of my device-is, that; owing to the construction and arrangement of the impeller units, the fiuidis progressively energized by each of the impeller units inthe series through which the said fluid passes from inlet'to exhaust, and at -the same time one of the impeller units is in opposition to the impeller units preceding in the series. In other words. while each of the successive impellers add pressure to the fluid. progressively. one of the same series of successively arranged impeller units is adapted to discharge the fluid in opposition to that of the other members of its series as relates to the end thrust of the shaft, thereby obtaining a further balancing by reason of said reverse discharge. I

It- .will be seen that throughout my description I have referred to the separate im Patented Jan. 20, 1914. i

pcllcrs and their fixed disks as pump unit's,

said 'pump units being literally an assemblage of parts arranged to receive the fluid, srpply force thereto, and discharge the same,

and it is for the purpose of distinguishing.

this -m=t-uction or assemblage from that as iudicai cd by the expression impeller units or impeller members. which constitute one of the parts it the said pump units that I make use of the above noted expressions.

, In connection with the above described means:- for securing the minimum amount of end thrust on the shaft and in order to secure the rotating parts in that fixed position relative to the stationary and co-actin parts of each, which will give the greatest e ciency to the pump, I provide a thrust bearing for the shaft, located in a chamber where means for lubrication is provided. This thrust bearing, owing to the balancing of pressure on the opposite sides of the im ellers as above mentioned, is enabled to maintain the impellers in the before mentioned well defined positions with the smallest amount of friction and wear.

While in the present instance I provide an end thrust bearin on themain driving shaft of said pump, an which isshown as the conventional type of ball thrust bearing, any practical type of thrust bearing which'will performthe required work in a satisfactory manner will answer the purpose for which I have adapted the same. This bearing is for the purpose of obtaining'the before men-.

tioned steadiness of positron of the impeller members and is intended to rigidly maintain .the impeller members in-fixed rotative; lanes in relation totheir co-acting parts, t at is, the fixed directing, disk members against which they may come in rotating contact, and by reason of the said thrust bearin this contact neednot be absolute but may e set to the smallest amount of clearance eonsistent-to the-reduction of friction and wear.

In the accompanying drawings Figure 1 is a sectional view ofmy improved centrifugal pump. Fig. 2 is a section taken on line 2-2, Fig. 1, looking in the direction of the arrows. Fig. 3 isa section taken on line 3-3, Fig. '1, looking in the direction of the arrow. Fig. 1 is a rear view of an impeller member. Fig. 5 is a section'ol the same taken on line-4.4, Fig. 4; Fig. 6 is a sectional view of the opposing or balancing member of a similar form to that shown in Fig. 4. Fig. 7 is a front view of one of the fixed directing disks. Fig. 8 is a section taken on line 7-7, Fig. 7. Fig. 9 is a fixed directing disk for the reversed or balancing impeller member 9.

In Fig. .-is shown one of the impeller members, the construction of'all of which in this pump are similar. The impeller members are shown as having only three wing members 50, 51, and 52, but a. different number may be used.

- I have found it desirable in practice to provide a number of intermediate series of shortwingmembers 53, placed intermediate of the main wing members 50, 51, and 52. These intermediate. members are comparatively short and only bridge the openin and further, are for the purpose of ai ing the main members 50, 51, and 52 in presenting the fluid for the action of the. guiding blades 65 011 the fixed fluid directing disks 66. The impeller 4 receives the fluid ata point 55 near the center, and the fluid entering the interior of said impeller passes out- 'wardly between the impeller wings 50, 51, and 52, as indicated by the arrow line. 56, and is then carried sidewise as indicated-by arrow 57 until it reaches the discharge point,

rect line and causing it to go in the direction .of thebefore mentioned arrow 57.

In Figs. 4 andj. is'shown a hub 63, said hub forming one wall of the annular inlet passage 51, and integral with the wall 62, and having a key-way 64 therein for the purpose of keying the same upon the driving shaft;

In Fig. 6 is shown a reversed impellermember having a reversely extending hub wherein the fluid is taken in at the a'nnu-- lar inlet port 76 and going in the direction of the arrows 77 discharges-from-an overhanging ort 78, similar in construction to the port 04 in Fig. 5. It will be noted that in Fig, 5 the flllld crosses the face of the blades 50, 51, and 52 from the rearwardly located central port to the outer located peripheral port, thus making a transit diagonallv across the face of the impeller blades 50, 51 and 52, whereas in the impeller members shown in Fig. 6, the fluid enters at the central inner port and is discharged from the outer port 78, both the inlet and outlet beingonthe same side of the impeller.

In Fig. 7 the fluid directing guides 65, which are integral with a fixed disk 66, .receives the fluid from the overhanging discharge port 54 of the impeller member 4: and directs it towardthe -central inlet p'ort 67, it'being there received and taken up by the next impeller member.

In Fig. 8 is shown a sectional view of the fixed disk member 66, F ig. 7, the portion in full lines indicating the type of disk member which would be utilized with impeller member 4, whereas the dotted cylindrical portion 68 indicates the extension that would be necessary to receive and direct the fluid from the impeller member 4. into the reversed impeller member 6; This may be seen by referring'to Fig. 1. In Fig. 9 is shown a similar fixed disk member with its fluid directing guide 69 thereon, the only difference in this member over that of the previous mentioned being in the opposite direction in which the, said fluid guides 69 are arranged. It is'ob vious that if the impeller members are constructed alike as to their impeller wings, that wheirthey are faced against one another upon a shaft rotating in oneidirection that the fluid guides would have to be reversed to properly receive and direct the flowing fluid.

In Fig. 1 the fluid enters the inlet port and flowing in the direction of the arrows 2 through the inlet: port 3 enters the first im- 8, with its extcnded cylindrical extension 68.

I upon the fixeddiskQG andtaking'the course.

The fluid then takes thecoursc indicated by arrows 11 through the central port 12 formed betwecnthe hub and the cylindrical extension 68 of the impeller member 14 (which impeller member is ofthe'sa'me type as that shown in Fi t. 6 with its reversed hub 75, the

fluid being directed in the manner described for Fig; 6), and it is thereupon received by the directing guides 15 which are arranged of the arrowsflTit passes" through the discharge port'18.

At points 19, 20, and 21, Fig. 1, are shown surfaces where the rotating impeller mem bers/l, 4, and 14 are in rotative engagement with the fixed disk members 8, 10, and 16, a

certain amount of leakage of the fluid pressure takes place and enters the chambers 22f 23, and 24, formed at the outside of the sait impeller members and atone side thereof. A series of separating ring members 25, 26,

a'nd127, are placed between theends of thepump caps 28 and 29 and between the fixed disk members 8, 10, and 16, for thepurposc.

of maintaining a fixed predetermined spacing thcrcbetwcen and form thereby what I call balancing chambers.

The automatic balancing .feature previ- OHSly-DIQIIlIIOIlQd 1S- partly caused by the seepage-- or leakage .of fluid pressure by the joints 19, 20, and 21, into the chambers 22,

23, and :24, beforementioned, thus causing pressure tobc accumulated in the said chambers. During the operation of this pump I have found that it the first. impeller member 4 gives a pressure of about 10pounds,the second impeller would give a-pressure of about 20 pounds. and so ml 1/71.. and it is due to the fact of this increase of pressure in the sum wording ll'lll'l'JllCiS that. Ian] enabled to equalizc the pressure throughout, for instance in jhc chamber 22 of the impeller 1 the pres-- sure tlwrcindue to the leakage from impeller 4, would be about 7 pounds and conversely, in chamber 23 the pressure would be about 15 pounds, due to the pressure in impeller member 4-, and in chamber 24 of the impeller member 14 the pressure there-in would be about 26 pounds.

The method by'w-hich obtain a balance on the impelling members and thereby relieve the thrust bearing of all undue strain except that of keeping the impellers in their proper rotative place is as follows: The pressure in chamber 22 of the impeller t and in chamber 23 oi" thc impeller 1', tends to offset the'pressure in chan'iber of the impeller 14. The pressure in said chamber in; the space adjacent to the periphery of the impe'llcrs can be neglectedentirely because the pressure theregenerated is between the inner wall of the supporter rings 26, and 27, and the said peripheries and therefore neither adds to nor subtracts from the endthrust on the shaft 39.- The back walls A-A of impelh rs 4 and 4 a nd the back wall 79 pf the impeller 14:, are the areas effe'cted by the pressure in said chambers. Itis furthermore to be understood that the pressure in these chambers is somewhat less than thatgenerated in their respective impellers, as has been previously noted. It

will further be noted that the area presented by'these back walls A-A and 79 also vary somewhat. I i For the,.purpose of bringing out the arrangement of pressure whereby I obtain the aforesaid balancing I ,will introduce a few figures. It will be understood that these figures are only approximate but are entirely in proportion to those that l have found in practice. If, as was previously stated, the pressure generated in the first impeller is 10 pounds, that in the second about .20 pounds, and that in the third chamber about 30 pounds, then thepressure in the (llillllbers- 22, 23, and 24, would be about 7, 1.5,.

and 26 pounds per square inch, respectively. Taking asquare inch of area of the pressure sides .-\-i\ and 79. neglecting for the moment the actual areas of the in'lpeller members, which are nearly equal, we would then have a combined prcssurepcr square Tich on the side walls A of the impellers 4 and 4' of pounds, and on the wall 7 of the impeller lll(ll'll)01 14, a pressure of 56 pounds per-square inch, thus caving a ditfcrcncc of 4. pounds pressure in favor of the impeller inen'ibcr 14. For the purpose of further oil-setting this extra pressure of the impeller member 1'4, I connect the passage- '\\-'ay 30 H) the side wall of tho-housing l from the impeller member '14 to the impeller member 4 by means of twoports 31 and 32.

As above stated, the pressure in chamber 22 of the impcllcr member 1 would be nbmli T pounds and that in the chamber 24 of tho inipcllcr member H, 20 poundMihc diil'crcncc-therebctwecn being 1! pounds infarcr of chamber 24. By permitting this excess fluid pressure from chamber member 24 to enter the chamber 22, a further balancing etl'ect; is obtained, the pressure in the two chambers becoming very nearlv equal. Still -l'urther pressure is to be considered, namely,

the pressure in the chambers formed by the lluid guides on the fixed disk members 8, '10,

and 4 to the left hand and the impeller.

member 14 toward tlie'right hand.

There. is a further discrepancy of areas in the walls (32 of-t-lie impellermembers 4 and r and the wall 81 of thc impeller member H. This discrepancy requires a further adjusting to cause a balance on the different impeller members.- To obtain this further refinement and to permitof yariable adjustment of this pressure to meetlhe varying conditions under which such a pump may operate. such as differences inlift, shot-ion lift and differences in pressure or head, I arrange a port 34- which connects the pressure chamber 23 of the impeller member 4: with the exhaust chamber 18, the pressure in said chamber being equal to that of the last impeller 14 and consequently is greater than that in the chamber 23, so by adjusting 'the valve member 35 which controls theport 34 and the set-screw 37 which controls the port 36, higher pressure from the chamber 18 is adjustably regulated and permitted to enter chamber 23, thereby causing a further pressure toward the right hand side of the pump. 1 have found in practice that I am enabled by this valve arrangement, to

over-come a left hand thrust that -would be natural in a pump of the'herein disclosed construction and cause the pressure to become an opposing one, or I can maintain.

with in any pump of a given capacity, andthat I am enabled, by my present construc tion, to cause the internal forces, which may naturally operate to cause an over-balance in one direction as regards the direction of end thrust, to,be created inan opposite direction to a balance, or in excess.

Various methods have been adopted heretofore forthe purpose of securin a minimum of endithrust on the shaft of cent-rifugal pumps, but these methods have difi'ered widely fromthatshown in the present application, as will be seen'from the following statement. I

Two kinds of impellers have been in use in multi-stage centrifugt pumps, one type of impeller being arranged to dischar e radially outward, that; is, outward at rig t angles to the axis of the impeller. In impellers of this type-the discharge cannot possibly have any direct influence-upon the end thrust of the shaft which is rotatably mounted at right. angles thereto. The other type of impeller is one arranged to discharge axially, that is, in a direction parallel to the axis of the impeller and its shaft. In this type of impeller the discharge has a positive and direct influence uponthe end thrust; of the shaft, the'said influence being exerted upon an area of ,the impeller equal to the area. of its discharge port.

i From the above noted statements it will be seen that the first noted im eller has an indirect influence as relates to t e end thrust of a' shaft, and the second noted impeller has a direct influence as relates to the end thrust ofa shaft, and therefore to distinguishofie f cm the other one may he termed indit, to distin ish it from the other, the

said indirect in uence being caused by fluid ressure accumulating on each side of the impeller, due to leakage at the point where the edge of the impeller near its discharge port is adjacent to other cooperating parts. This indirect pressure'on the sides of the impeller is equal per square inch of area on all the area. subjected to it, but the area affected is greater, on one side than on the other.

Ifthe impellers discharge radially outward, the end thrustiscaused by suction and pressure-of-equal poundsper inch on allopposing sides of'impellers of unequal area. If the impellers discharge axially the end thrust is caused by suction. In a pump having an axial discharge a balance. more or less perfecthas been secured by having two series of pump units on the same shaft, one of the series being opposed to the other in the direction of discharge, each series .having an independent suction pipe, one at either end of the pump case and discharging into a volute chamber surrounding the two central impellers of the series. the flow of the central impellers being radially outward inthe volute discharge chamber.

In a pump of the radially outward discharge type, the passageways from the discharge po-rt of one impeller and the inlet port .is first outward, then axial, and then inward towardt-he center of the pump, and the above is true whether the impellers are arranged in' pairs opposed to one another, or in any other relative position. -The said passageway is necessarily 1ong,.circuitous, and of a thin cross section, presenting a large amount of surface to the volume of flowing water, causing a large amount of sk n friction and a corresponding loss of elnciency in thepump. Inncither case can there be any re-act-ing effect on the said impeller as the discharge leaves the pump unit 45 completely ba and flowing toward the outer port of the pump unit-1s in a fixed partition that has a portion which separates the outlet port from the chamber in which the impeller revolves, 5 and also the pressure at the outlet port side of the pump unit is less than at the point of discharge of the impeller, and of about equal pressure to that in the chambers at the side of the impeller. In the .present noted construction the passages from the outlet of one impeller to the inlet of the succeeding impeller is direct with the smallest amount of obstruction to velocity of the fluid movingtherein, and 5 forms the shortest possible route in which the flow maybe directed, and-is of such cross sectional area that a minimum amount of. skm friction is presented to the movlng volume of water. Hence the skinfriction of thepassages is" less and theefiiciency' of the pump is greatly increased. The above noted construction and arrangement of parts while contributinglargely to the efficiency of the pump, also-provides a 2 simple and effective method of eliminating the end thrust on the impeller shaft'and the detrimental consequences thereof. The full force of the direct'pressure of discharge and the re-acting effect as vit leaves the pump unit, comes upon the discharge port side of-the impeller. The-oppositeside oft heimpeller and this 'alone' receives the indirect influenceof the discharge due to leakage between the impeller near'its discharge port and the parts iiext adjacent-thereto. This] leakage collects in the chamber arranged in the pump unit on the side of the impeller opposite to the discharge port side, and to' the extent of the pressure ill-fills chamber 40 the id pressure becomes'a balancing forceto the pressure on the discharge port side.

The reversal of the last pump unit-ofthc' series, as "relates to the direction of the flow of its discharge, pro-ides a ready means of ancing the pump whereby the ressure in the last balancing chamber of e series is transferred to the first balancing chamber in the same series, or to the other impeller balancing chambers if so deo sired.-

The reversal of the lastpump unit of. the

series also provides a. natural space for the' unit being located in that side. wall of the impeller which is nearestto 'the preceding unit.

In a centrifugal pump comprised of a housing havingan inlet port, a plurality of impeller.members rotating in said housing, o eof the said impeller members discharging'iuan opposing direct-ion to all the other impeller members, through a discharge port in-the impeller located in one of the side walls of the impeller and near the periphery thereof,,'iuto a ring-shaped chamber counccted with the discharge port of the pump.

In a. centrifugal pump comprised of a housing having an inlet-port, a plurality of impeller members rotating in sald housing, one of the said impeller members discharg- 'ing in an opposing direction to all the other impeller members through a discharge port in tllQ'llllPOllQl' located in one of the side walls of the impeller and near the periphery thereof, into a ring-shaped chamber connect 7 ed with the discharge port of the pump, said I ring-shaped chamber being located between the aforesaid'impeller and the other i-mpellers with which it is associated. 4. In a, centrifugal pump, a pump unit consisting of an impeller whose discharge ort 1s located in one side wall ofthesaid impeller and near the periphery thereof, a stationary disk having guide blocks thereon to direct the flow to..a centrally located outlet port in the disk, and a balancing chamber located'at the side of the impeller that is opposite to that in which the discharge port is located.

5. In a centrifugalpump, the combina- 7 tion of two pump units which are opposedly arranged as relates to their discharge. each pump unit having a centrally located inlet port and a centrally located outlet port, an a impeller fixedly mounted upon a shaft for rotation, said impeller having a centrally located inlet-port and'a discharge port located near the periphery thereof discharging radially inward. and guiding blades to cause a ,continued flow of the fluid toward the centrally located outlet port.- the said outlet port o'f'each pump unit being adjacent to the centrally located outlet port of the other ump unit.' 6.

n a centrifugal pump, the combina tion of a housing, a shaft uitably. mounted T therein forrotation, two'or more impellers fixedly mounted on the shaft and fixed disks disposed intermediately of said impellers and having arranged thereon guiding blades to radially direct the flow of the transmitted fluid for each impeller, one ofthe said impellers with its fixed disks and guiding blades being reversed as relates to the other of said disks and as regards-the direction of its discharge, whereby thepressiu-e of the dischargeof one impeller has a couuicracting effect on the pressure of the discharge plurality of pump units, one of said stationary disks having .a centrally located tubelike extension which for-ms the outlet port-of one part of the unit, said tube-like extension f passing through-the outlet port of the next I succeeding pump unit making a moving con- 'neetion with the inlet port. of the next succeeding impeller.

S. In a centrifugal pump, a shaft suitably mounted forrotation, having two or more impeller members fixedly mounted thereon, each of the said impeller members having a discharge port locatedin one side wall of thesaid impeller near the periphery thereof and facing to discharge radially inward, two of the said impeller members being so placed on the shaft that the discharge-port side of each impeller shall be adjacent to' and facing the other impeller. 9. In a centrifugal pump, the combination of an impeller having an annular casing with end walls, a discharge port located near the periphery of the impeller, and in the outer wall ofa recess formed in one of the end walls of the impeller, and an inlet port centrally located in the same end wall of the impeller. I

10. In a centrifugal pump, the combination of a shaft suitably mounted for -rot a tion, two or more impeller members fixedly mounted on the shaft, and a stationary dis arranged to 006 erate with each impeller, each stationary isk having guiding blades tliereon to guide the flow'of the transmitted fluid toward the centrally located outlet port in the said disk, one of the impellers and the guiding blades associated with it being con structed and arranged'to discharge in a direction opposite to the discharge of the other 'j impellers with reference to the end thrust of the shaft.

11. Ina centrifugal pump, two pump units which are .opposedly arranged as relates to their discharge, each of thosaid pump-units having a centrally located-outlet or discharge port, the said outlet port oil "ach unit being so located that it shall be adjacent to the outlet port of the other unit.

nd the discharge therefrom of eachshall;

flow toward the outlet port of the otherin a direct axial line.

19. A centrifugal pump having an inlet and discharge port, and a series of;pump units organized to energize fluid progressively from the inlet to the discharge port, a ring-shaped discharge chamber. connecttween two of the pump units of the series, the diametrical inner wall of the said chamber being a centrally located tube extending from oneof the pump units to the other two said pump units.

13. A centrifugal pump having an inlet and discharge port, and a seriesof pump units organized to energize fluid progressively from the inlet to the discharge .port, a ring-shaped discharge chamber connecting with the discharge port of the pump, the said discharge chamber'being located between two of the pump units of the series, the diametrical inner wall of the said. chamber being a centrally located tube extending from one of, the pump units to the other of the; two said pump units, the said tubular member forming a passageway from the outlet port of one pump unit to the inlet port of the next pump unit of the series.

14. The combination of a centrifugal pump having an inlet and discharge port, of a series of pump units organized to energize fluid progressively from the inlet to the discharge port of the pump, an impeller located in one of the said pump units" and suitably mounted for rotation, the said 'imeller having a centrally located inlet port. in that wall of the said impeller that is nearest to'the preceding pump unit ofthe series, and'an outlet port located'near the periphery'of the impeller and in thefsame wall-of the" said impeller as the inlet port.

' 15. The combination of 'a centrifugal. pump havingan inlet and a discharge port, of adischarge chamber'connecting with-the discharge port of the pump, and a-series of pump units organized to energize fluid progressively from the inlet to the discharge port, one of the series of pumpj'unitshaving an outlet port centrally located'in one wall of the said pum units and projecting across the discharge c amber to connect the-said unit with the next succeeding unitof-the series.

16. In a centrifugal pump having an; inlet and a discharge port anda plurality of pump units, a ring-shaped discharge chamber connected with the discharge port and located between two of thesaid pumpunit's the side walls of the said discharge chamber being the stationary disks in which are centrally located the outlet ports of the two pump units between which the discharge chamber is located,

'17. The combination of a rentiifiigal pump having an outlet and a discharge port, of a seriesrof pump units organized tofciier benconnectc'd with the discharge'port and located between two of the pumpmnits of.

the series, one of the series of pumpunits' ing with the discharge port of the pump, 1 opposed to the other unit of the series as .the said discharge chamber being located be i relates to the direction 01' flow ofdts-disgize fluid progressively from th'eirlet. .to the d scharge ports, and a discharge 'chamcharge, the said opposed pump unit having a centrally located inlet port in the wall nearest to the preceding pump unit, and an outlet port in the wall nearest to the preceding puinp unit of the series, the said outlet port discharging axially into the discharge chamber in a direction toward the last preceding pump unit of the series.

18: The combination in a centrifugal pump having an inlet and a discharge port and a series of pump units, of a discharge chamber connected with the discharge port and located between two of the pump units of the series, a pump unit located on one side of the said discharge chamber, the outlet port side of the said puinp unit being toward the said chamber and having an extended portion at the outlet port to conduct the discharge of the next succeeding pump unit, and a pump unit located at the opposite side of thesaid chamber from the preceding unit, said last pump unit having an inlet port adapted to receive the fluid from the extended outlet port of the preceding unit and having an outlet port in the wall nearest to the said chamber, said outlet port adapted to discharge axially into the said discharge chamber.

-19. The combination in a centrifugal pump having an inlet and discharge port and a discharge chamber connected with the discharge port, of two pump units that are opposedly arrangedasrelatcs to their dischargeieach pump unit having an inlet and an outlet port, impellers rotatably mounted in said pump units, each impeller having. a centrallylocated' inner port, also a discharge port located near the periphery thereofland a stationarydisk having guiding blades thereon to direct the flow of the -transmitted fluid toward a centrally located port in the disk, said port forming the outlet port of the pump unit, the stationary disks of the two pum units forming the side walls oi the said ischarge chamber.

20. In a centrifugal pump having a plurality of impellers suitably mounted for rotation, each of the said impellers havinfta discharge port in one side wall of the 1mpeller and hear the periphery thereofljand having a balancing chamber for each impeller, the said: balancing chamber being located at the side of the impeller that is opposite to that in which the discharge port of the impeller is located, a ring-shaped discharge chamber connected with the discharge port of the pump' and located between two of the impullers which are so mounted that the discharge port of each shall be in the side of the impeller nearest to the dischar e chamber, and a conduit connecting the alancing chamber of one of the said impellers with the balancing chamber of an impeller that is located on the opposite side of the discharge chamber.

21. In a centrifugal pump having an inlet and a discharge port, a series of pump units organized to energize fluid from the inlet to the diseharge port of the pump, in which each unit of the series has an impeller whose discharge port is located in one of the side walls of the impeller, and near the periphery thereof, a stationary disk having guide blades thereon to direct the flow radially inward to the centrally located outlet port of the unit, and a balancing chamber located at that side of the impeller that. is opposite to the discharge port side of the impeller, the last balancing chambers of the series being opposedly arranged to all the other balancing chambers in the series with rel-en the shaft.

A centrifugal pump comprisedof a housing, a shaft rotatably mounted therein. a series of impeller members fixedly mounted on the said shaft for rotation therewith, each of the said impellers having a discharge port located in one of the side walls of the. said impellers and near the periphery thereof, whereby the full pressure of the discharge due to the action of the impeller is exerted on the discharge port side of the impeller to cause an end thrust of the shaft, a'ud having the last impeller of the series opposedly arranged to all the other impellers on the end thrust of the shaft.

A centrifugal pump comprised of a housing, a shaft rotatably mounted therein, a series of pump units therein, each pump unit of the series having an impeller fixedly mounted on the said rotatable shaft, each of said impellers having a discharge port located in one side wall of the impeller and near the periphery thereof, whereby thefull of the impeller is exerted on the discharge port side of the impeller, a balancing chamer in each pump unit ofthe series located at that Side of the impeller that is opposite the discharge port side of the impeller, and having one of the balancing chambers -.in the series opposedly arranged to theother balancing chambers of the series with refv erence to its influence on the end thrust of the shaft, a passage-way leading from the balancing chamber of the opposedly arranged unit to one or more ofthe balancing chambers in the other units of the series.

CHESTER COMSTQCK. lVitnesses:

wJ'oim Mourns,

FRED. J. Dom

of the series with reference to its influence pressure of the discharge due to the action.

once to its influence on the end thrust of A 

